Photozone publsihed the full Laowa 7.5mm f/2 MFT lens review. This lens is yet not available for preorders but Photozone says it will start shipping out in April. And this ic part of the conclusion:
The primary value proposition of the Laowa 7.5mm f/2 MFT is certainly its extremely small size and low weight combined with a very large max. aperture. Upon unboxing, we experienced one of the few WOW effects during recent years. The dwarfish size also makes perfect sense on Micro-Four-Thirds cameras. Despite its size, the delivered resolution is actually very respectable. It’s usable at f/2 and very good at medium aperture settings. The amount of lateral CAs is decent. The vignetting is very high, yes, but in reality it’s not quite as bad as the numbers suggest because of a relatively gradual light falloff. Image distortions can be visible in certain scenes but they are far from being bad really. Ghostings/glarecan be an issue if a strong light source is part of your scene and that can happen often due the immense field-of-view.